Simulating the impact of scattering on the angular distribution of Cherenkov radiation

We present a study of the impact of scattering on the emission of Cherenkov radiation, explore the limitations of the simulation tools currently in use in particle and nuclear physics, and propose a method for overcoming these limitations. We start with a derivation of the Cherenkov power spectrum and its angular profile, accounting for interference of the radiation emitted, in contrast with commonly used tools that assume perfect coherence. We then study the impact that the path of electrons through a medium has on the angular profile of Cherenkov light. Finally, we devise a model that can incorporate these effects into Geant4 and tune it to explain calibration data from the water-phase of SNO+. We find that the tuned model significantly improves the agreement between data and simulation, so we provide it for its wider use. • We show how Cherenkov angular distributions depend on coherence assumptions and scattering models. • We introduce a fast algorithm that improves Cherenkov angular modeling with minimal cost. • Applied to SNO+ calibration data, the method significantly improves data–simulation agreement.